Stray voltages have been identified on farms that raise cows. Stray voltages may arise from the utility power distribution system In addition, electrical faults of electrical equipment, such as poor electrical connections, corrosion of switches, and frayed insulation, may also create stray voltages.
Because of stray voltages, a voltage potential may be introduced across a cow. As a result, electric shocks are applied to the cow, and more specifically, to the teat of the cow. Although the cow is not necessarily injured physically, the cow will react negatively during milking and tend to withhold its milk. In addition, the cow may become conditioned to the adverse environment and as a result may resist with physical violence against being moved into the milking area.
FIG. 1 illustrates an example of a conventional milking system 800 that is attached to a cow 810 when milking is performed on the cow 810. The conventional milking system 800 includes at least one liner 860 connected between a teat 840 of the cow 810 and a claw 870, a flexible plastic tube 880 connected between the claw 870 and a stainless steel, milk pipeline 820, and a milk tank 830 into which the pipeline 820 deposits milk from the cow 810 and other cows that are indicated by X's. Typically, the milk tank 830 is remotely located from the cows.
FIG. 2 is an enlarged view of a conventional milking system 100 that is attached to a teat 40 of a cow (not shown). In FIG. 2, a rubber liner 42 is connected between the teat 40 and one of four milk receiving holes 48 of a claw 50. Note that only two admission holes of the claw 50 are shown. In addition, the rubber liner 42 is partially surrounded by a shell 72 that is typically formed from aluminum or stainless steel. The enclosure 72 has a suction hole 71 connected to one of four air admission holes 46 of the claw via a flexible plastic tube 70. Note that only two air admission holes are illustrated. With respect to the claw 50, it also has two pulsation holes 43 that are connected to a pulsator (not shown) that is in turn connected to a vacuum (not shown). Although FIG. 1 only shows the connection between the claw 50 and only one teat 40 of the cow, up to four teats may be connected to the claw 50 for milking. Typically one claw is used for each cow.
When milking is desired, the vacuum is turned on and operated in conjunction with the pulsator so as to produce pressure changes within the enclosure 72. As a result, the rubber liner 42 is caused to squeeze and then release the teat 40. Consequently, milk 44 comes out of the teat 40 and a milk stream 45 moves along the rubber liner 42 toward the milk receiving hole 48 and into a milk chamber 47 of the claw 50. As explained above, other teats of the cow also provide milk through the other milk receiving holes 48 of the claw 50 so that the milk chamber 47 usually has some milk deposited therein. To drain the milk chamber 47, the milk chamber 48 has a duct 52 connected to a tube flexible plastic tube 54 for transporting the deposited milk to a milk pipeline (not shown) that also receives milk from other cows via flexible plastic tubes similar to the flexible plastic tube 54. The milk within the milk pipeline eventually is deposited into a remote milk tank.
As the deposited milk within the milk chamber 47 is drained through the flexible plastic tube 54, a continuous milk stream is formed from the milk chamber 47 to the milk tank. This milk stream provides a conducting path for any current that may be generated by a voltage potential difference between the cow and the milk pipeline. As a result, an electric shock is applied to the teat 40 of the cow when the milk 44 makes contact with the milk stream 45 flowing to the milk chamber 47.
As apparent from the above discussion, a need exists for a milking system and a method that reduces electric shocks to the cow when milking is performed on the cow.